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'112, 1930. original Filed Dec. 16, 1926- Re. 17,765

, I VENTOR l l W ATTOR EY Reissued ug. 12, 1930 y UNITED STATES SAMUEL HAMMER, OF BROOKLYN, NEW YORK, AssIGNOR, BY MESR'ASSIGNENTS,

Re. uns

PATENT VrOFFICE;

TO ROACH-APPLETON MANUFACTURING COMPANY, OF CHICAGO, ILLINOIS, COR- POBATION 0F ILLINOIS y KNOCK-OUT FOR ELECTRIC JITNCTION BOXES, SWITCH BOXES, vIE'I'G.

Original No. 1,721,593, dated July 23, 1929, Serial No. 155,163, filed. December 16, 1926. I v reissue led March 20, 1930. Serial No. 437,615.

This invention relates to knock-outs for electric junction boxes, switch boxes, etc., and has for its primary object to provide one or more walls of the box structure with integrally connected sections or discs which may be readily detached or separated'from the box wall to provide openings therethrough for .the lead-in wires Without necessitating the use of a hammer.

It is a more particular object of the invention to provide each of the knock-out discs or sections with an outwardly projecting part or lip with which the point of a screw-driver may be readily engaged and the necessary leverage applied to separate said disc at its perimeter from the box wall; thus the box structure is not subjected to a severe shock or vibration which might possibly result inI injury or derangement of the parts of the mechanism associated therewith, which is not an infrequent occurrence when such junction boxes are used in connection with electrically controlled clocks or other comparatively delicate mechanisms.

' It is a further general object of my present improvements to provide a knock-out tor electrical junction or switch boxes as above characterized which involves no additional operations" in the present method of manufacturing such boxes, and therefore entails no additional manufacturing cost.

With the above and other objects inview., the invention consists in the improved knockout for junction or switch boxes and in the form and construction of the several features thereof as will be hereinafter more fully described, illustrated in the `accompanying drawings and subsequently incorporated in the subjoined claims. fr

In the drawing, wherein I have disclosed one simple and practical embodiment of my present improvements and in which similar reference characters designate corresponding parts throughout the several views,-

Figure 1 is a front elevation of an electric switch box provided with my present improvement and showing the cover in open `position; 5 A Figure 2 is an enlarged elevation of onev Application for of' the box walls provided with my improved knock-outs;

Figure 3 is an edge view thereof, and Figure 4 is adetail sectional view taken on the line 4 4 of Figure 2. j

Referring in detail/.to the drawing, 5 generally designates the body of the junction or switch box, theseveral walls of which are in the form of sheet metal stampings. To the side walls of the box body 5 at one end there-Y oi", the cover or closure for the open side of the box indicated at 6 is hingedly connected.`

Further detailed description of the box construction is unnecessary, as the invention conlof the stamping die and partially projected from the general plane ot the box wall, as

clearly shown in Figure 4 of the drawing.v

However, these discs at their perimetersremain integrally connected with the wall structure by a comparatively thin iin of metal as indicated at 8. The line of rupture of the metal, it will be observed, lies along a single line. This weakened connection between vthe discs and the box wall will permit the coniplete separation of the discs fromsaid wall by the application of leverage or pulling eect to the edge of the'disc. In order that such leverage or pulling etl'ect may be readily applied, a minor part of the disc at its edge isv completely separated from the box wall and angularly projected outwardly beyond the plane of said disc to form a lip 9. The portion 8 constitutes an intact portion which is disrupted in the removal of the corresponding sectionl 7. Said lip 9 is symmetrically disposed relative to said portion 8.

In the use of such electricaljunction boxes in connection with electrical clocks or other mechanisms, the box is suitably mounted within the clock case, and in the installation of the clock the discs 7 are removed from that wall of the box so as to provide the openings therethrough most conveniently located with respect to the arrangement of the wiring in the building, vso thatthe lead-in wires may t ly connected throughout their'circumferential edges with the box wall, and it has been necessary to remove said discs by striking the same several severe blows with a hammer.

It has been found that in' many cases thisresults through the jar or vibration,in derangement of the parts of the delicate clockv mechanism, and as the space in which theA hammerk may be wielded is comparatively restricted, there is also great liability of the hammer striking parts of the mechanism and t seriously damaging the same so that` they have to be replaced. Itjwill be apparent lthat by means of my present improvements it is not necessary to subject theA box structure or the casing within which it is mounted to such severe vibrations, :as the discs 7 can be readily removed by merely inserting the point of a screw-driver or other implement,

as indicated at l0, beneath the vlip 9 and prying outwardly while the point of the screwdriver is in bearing'contact against theface of the box wall. Thus, the relatively thin. iin 8 at the perimeter of the disc-may be ruptured and the disc completely separated from the box wall to provide the necessary opening therein.

It will be apparent that this operation may be very quickly performed without the slightest jar or vibration of the box structure so that there is no possibility of injury tol parts contained therein or to the mechanism which may be associated there- From theV foregoing description considered in connection with the accompanying'drawing, the construction and manner of use of 4Wise, the particular shape and size of the disc 7 or the form and arrangement of the lip 9 or other means with which the tool is` adapted tov be engaged is not material and may be variously modifiedas may befound desirable Ato satisfactoril meet dirent conditions. Therefore, w ile I have herein shown and described one simple and practical embodiment of the device which has given excellent results in actual use, it is nevertheless to be understood that the invention is susceptible of embodiment in various other alternative forms, and I accordingly reserve the privilege of resorting to all such legitimate-changes in the essentialfeatures thereof as may be fairly embodied within the spirit and scope of the invention as claimed. lVhat is claimed is- 1. A metal container for eletrical apparatus having a wall with a removable portion marked out thereon, said portion being integral with said \wall and connected therewith around the greater part of its periphery by a metal n which is thin enough to permit the ready separation of said portion of said wall, said fin being too thin to permit bend-v i ing Without breaking, the `remaining portion of the periphery being bent to rm a lateral projection to permit an implement to be inserted Vunder said said portion. i v 2. A metal structure having a wall with a removable portion marked-out thereon, said portionbeing integral with said wall and connected therewith by an intact portion to permit the ready separation of said remov- Iable portion from said wall,.the remaining portion of the periphery otsaid removable portion being formed to provide an abutment to permit an implement to be engaged `tl'ierewith to break out said removable portion.

, 3. In a ymetal structure, in combination, va wall portion having a removable portion forming part thereof, said removable portion being defined by a single line of rupture interrupted by` a single intact'portion, the edge portion of said removable portion symmetrical with said A intact portion beingy formed with means for engagement with a tool for breaking out said knock-out.

4. A metal structure having a wall portion provided with a removableportion, said removable portion being defined by a single line of rupture, the edge portion ofsaid removable portion-being formed with an abutment for the reception of a tool for breaking out said knock-out. i

5. A metal structure having a Wall portion /providedwith .a removable portion, said removable portion being definedby a single line of rupture, said removable portion being formed, symmetrically with said line of rupture, with abutment means for. thereception of a `-tool fr breaking out said knock-out. N 6, A metal structure having a wall portion provided with aremovable portion, said removable portion being defined by a single line of rupture, arl/edge portion of said removable portion symmetrical with reference to said line of rupture being formed with abutment means for the reception of a tool for breaking out said knock-out. i

' 7. In ca metal struct-ure, in combination, a

projection to break out wall portion having a removable portion I forming a part thereof,.said Oremovable portion being defined .by a single line of rupture interrupted on one side only of said removableportionby a portion symmetrically disposed relative to saidline of weakened-material, said one side of saidl removable portion being formed with means for engagement with a tool for breaking out said knockout.

8. A metal structure having a wall portion provided with a removable portion, said re-v movable portion being defined by a single line of rupture having the outline o a. geometrical figure, said removable portion being formed on one side of said geometrical gure with an abutment for the reception of 1 a tool for breaking outvsaid knock-out.

Signed at Brooklyn, New York, the th day of March, 1930. f

SAMUEL HAMMER. 

